The invention relates generally to electronic devices, and more particularly to organic electronic devices.
In recent years, organic electronic devices, such as, but not limited to, organic light emitting devices, organic photovoltaic cells, organic electrochromic devices, organic transistors, organic integrated circuits, or organic sensors, have attracted much attention due to low cost and compatibility with flexible plastic substrates.
Currently, organic electronic devices, such as, but not limited to, organic light emitting devices, are being increasingly employed for applications, such as display applications, for example, flat panel displays and area lighting applications. In the last decade, tremendous progress has been made in the area of organic electronic devices. Previously, liquid crystal displays (LCDs) were employed for most display applications. However, the fabrication of LCD displays often involves high production and commercial expenses.
With the imaging appliance revolution underway, the need for more advanced handheld devices that combine the attributes of a computer, personal digital assistant (PDA), and cell phone is increasing. In addition, the need for new lightweight, low power, wide viewing angle devices have fueled an emerging interest in developing flat panel displays while circumventing high production and commercial expenses associated with liquid crystal displays. Consequently, the flat panel display industry is looking to employ new displays utilizing devices from other technologies such as organic light emitting devices.
As will be appreciated by one skilled in the art, an organic light emitting device, such as an organic light emitting diode (OLED) includes a stack of thin organic layers sandwiched between two charged electrodes. The organic layers include a hole injection layer, a hole transport layer, an emissive layer, and an electron transport layer. Upon application of an appropriate voltage to the OLED, typically between 2 and 10 volts, the injected positive and negative charges recombine in the emissive layer to produce light. Further, the structure of the organic layers and the choice of materials for use as the anode and cathode are chosen to maximize the recombination process in the emissive layer, thus maximizing the light output from the OLED device. This structure eliminates the need for bulky and environmentally undesirable mercury lamps and yields a thinner, more versatile and more compact display. In addition, the OLEDs advantageously consume minimal power. This combination of features enables OLED displays to advantageously communicate more information in a more engaging way while adding less weight and taking up less space.
Applications, such as lighting and large area signage, may necessitate use of large area organic electronic devices. Typically, large area organic electronic devices include electrically coupling a plurality of individual organic electronic devices in series on a single substrate or a combination of substrates with multiple individual organic electronic devices on each substrate. However, the series electrical coupling between the plurality of organic electronic devices is typically achieved by formation of vias configured to provide desirable interconnection.
As will be appreciated, the selective patterning of the vias and the deposition of the conducting material may generate debris that may cause defects. Further, these fabrication techniques require additional processing steps to either selectively remove organic materials or selectively apply organic materials. Additionally, the formation of interconnections through the vias necessitates the precise alignment between layers of the organic electronic device. It becomes increasingly difficult to achieve the desired precision of alignment when the size of the vias and the feature size of the components of the organic electronic devices are reduced.
It may therefore be desirable to develop a technique to electrically couple a plurality of organic electronic devices in series to facilitate the formation of large area devices that advantageously circumvents the limitations of current techniques.